OAKLAND — Often it’s a Scout troop or a high school team operating a charity carwash, all youthful smiles, exuberance and joy.

Although heartfelt, the carwash and barbecue that snarled traffic Saturday on International Boulevard at 64th Avenue was no thing of joy. The volunteers put muscle and sweat not just into scrubbing cars, but into scrubbing a bloodstain from their neighborhood’s soul.

Dozens toiled all day to raise money for the family of Carlos Fernando Nava, the 3-year-old killed in his stroller, an innocent bystander in a drive-by shooting last Monday afternoon. Money aside, they seemed driven to show that their community stands united to cleanse itself of senseless violence.

“This was the point,” Jose Luis Nava, 26, the slain boy’s cousin, said as he directed traffic in and out of the lot. “Unfortunately, this happened to our family, but we want to stop this from happening to any other family. We’ve got thousands of kids walking these streets every day.”

On Saturday, they walked past a mountainous shrine of flowers, candles, stuffed animals and balloons erected at the spot where Carlos died, half a block from the carwash site.

Lawrence Denard, 26, a suspected gang member and parolee from Pittsburg with a criminal history that includes arrests for grand theft and being a felon in possession of a gun, was charged Thursday with murder in the boy’s killing.

The slain boy’s father, also named Carlos, was among many relatives helping out at the carwash Saturday but declined to be interviewed.

Many drivers honked horns in support or paused to hand donations out their windows, forgoing a carwash. Among the latter: an Oakland Fire Department ladder truck. That brought a nod of approval from DeeDee Wallace, 37, who said she was born and raised nearby.

“It’s gone too far anyway, but when it’s a child, it’s just too much,” she said. “We’ve seen too many deaths and now it’s a child; it makes no sense.”

Patrick Richards, 42, another local resident, was holding a sign and waving down cars. “For the little baby, for the little bambino,” he shouted.

“It took for this little baby to get hurt for all of us to come out here and be united,” he said. “You see people out here, all different nationalities together — you don’t see that often. But it could have been any of ours, it could’ve been anyone’s kid. They were just going to the store. That was a 3-year-old, man.”

Keli Arnold, 28, of San Leandro, waited with her son, Jaymz, 5, as their car was washed.

“If it was my baby, I hope everyone else would show up, too,” she said, squeezing her son’s hand.

The fundraiser resumes at the same site 11 a.m. to 7 p.m. Sunday.

A viewing for Carlos will be held from 6 to 9 p.m. Monday at Clarence N. Cooper Mortuary, 1580 Fruitvale Ave., in Oakland. A private funeral will be held Tuesday.

A Carlos Nava fund has been set up at the Wells Fargo San Leandro Marina Branch, account No. 3981855954.